The present invention relates to plant growth regulating preparations comprising
a) 0.1 to 20% by weight of a 16,17-dihydro gibberrelin of general formulae Ia or Ib
b) up to 99.9% by weight of an formulation additive selected from the group consisting of
b1) the reaction products of triglycerides based on carboxylic acids having 2 to 30 carbon atoms and ethylene oxide and/or propylene oxide in the presence of a base, and/or
b2) fatty acid esters of sugar alcohol polyethoxylates
c) up to 50% by weight of an organic solvent
d) 0.1 to 50% by weight of a formulation auxiliary different from b1 and b2,
e) up to 50% by weight of additional plant growth regulating compounds.
Furthermore, the present invention relates to the use of the said preparations for the regulation of plant growth.
Numerous plant growth substances are known. Part of these substances are used in agriculture and horticulture in order to induce desired effects, for instance on
seed germination and seedling growth
rooting
dormancy
juvenility, maturity and senescence
flowering
abscission of leaves, flowers and fruits
fruit set and development
tuber formation
growth of shoot and root
photoassimilation
control of unwanted plants
senescence of whole plants or single organs
[cf. R. N. Arteca (1996) Plant Growth Substances, Chapman and Hall, New York.]
Gibberellins (GAs) represent one group of plant growth substances. GAs occur naturally in higher plants where they function as phytohormones being involved in the regulation of growth and flowering and numerous other developmental processes. Certain GAs, particularly gibberellic acid or GA3 (ent-3xcex1,10,13-trihydroxy-20-norgiberrell-1,16-diene-7,19-dioic acid 19,10-lactone), are commercially available as fermentation products of the fungus Gibberella fujikuroi. 
C-16,17-dihydro GAs and related structures have been known since many years. They either occur naturally in higher plants (e.g. GA82 and and GA83) or in the fungi Gibberella fujikuroi (e.g. GA2, GA10, GA42) and Phaeospheria sp. (e.g. GA82).
WO 93/03616 and PCT/AU95/000528 describe for the first time the biological activity of known and newly synthesized 16,17-dihydro GAs and their potential utility for agricultural, horticultural and plant breeding applications. In particular the following biological effects have been described as features of the 16,17-dihydro GAs and/or other ring D-modified GAs:
dwarfing
growth retardation of stem and shoot and/or root
promotion of bud break
flowering
improved fruit quality
inhibition of fruit ripening
prevention of whole plant and/or organ senescence
improved fruit set
control of weed growth
inducing male sterility
retarded bud break
tillering
Further details on chemical and biological aspects of distinct 16,17-dihydro or other ring D-modified GAs have been published in the recent scientific literature.
A major obstacle to introduce the ring D-modified gibberellin derivatives described in WO 93/03616 and PCT/AU95/00528 into agricultural and horticultural practice is caused by the costs required to produce these compounds. The production costs are primarily affected by the price of the starting material GA3 [cf. W. Rademacher (1997): Gibberellins, in Fungal Biotechnology, T. Anke (ed.), Chapman and Hall, Weinheim, pp. 193-205].
There thus exists a need in formulations based oh ring modified D-gibberelin derivatives having improved biologicasl activity and thus better economical feasibility.
The object of the present invention was to provide plant growth regulating preparations based on ring D-modified gibberellin derivatives having a very good biological activity, in particular at low application rates.
This object has been achieved with the plant growth regulating formulations as defined in claim 1 and hereinbefore.
Preferred embodiments of the instant invention are set forth in the dependent claims and the following detailed specification.
The C-16,17-dihydro gibberellins (component a) have the chemical formulae Ia or Ib 
wherein A, B, C, D, E and F independently represent hydrogen atoms or hydroxyl groups and the dotted line represents one optional double bond either between the carbon atoms in position 1 and 2 or between the carbon atoms in positions 2 and 3, and 
wherein
R1 represents H or OH, OC(xe2x95x90O)R5 or OR5 
R2, R3, which may be the same or different, each represent H, F, Cl, Br, lower (C1-6) alkyl, lower (C2-6) alkenyl, lower (C3-6) cycloalkyl, or CH2X (wherein X is F, Cl or Br);
R4 indicates that the A ring may be (i) unfunctionalised, or (ii) contain a 1,2-double bond or 2,3-double bond, or (iii) contain a 3xcex1- or 3xcex2-OH, F, Cl or Br group with or without a 1,2-double bond, or (iv) contain a 1xcex1- or 1xcex2-OH, F Cl or Br group with or without a 2,3-double bond;
R5 represents C1-C6-alkyl.
The following compounds are particularly preferred in the preparation of the inventive preparations: 
The content of the component a) in the inventive formulations is in the range of from 0.1 to 20, in particular 0.2 to 10% by weight of the formulation.
As component b) the inventive formulations contain
b) up to 99.9% by weight of an formulation additive selected from the group consisting of
b1) the reaction products of triglycerides based on carboxylic acids having 2 to 30 carbon atoms and ethylene oxide and/or propylene oxide in the presence of a base, and/or
b2) fatty acid esters of sugar alcohol polyethoxylates.
The component b1 is obtainable by the reaction of an oil/fat based on a triglyceride of carboxylic acids having 2 to 30 carbon atoms and ethylene oxide and/or propylene oxide in the presence of a base. Fatty acid alkoxylates are primarily formed.
In the triglycerides, three equivalents of carboxylic acid are esterified with glycerol. The carboxylic acids can be saturated or mono- or polyethylenically unsaturated.
Preferably, the present invention uses naturally occurring oils and fats which contain triglycerides as the main constituent. They can be crude, denatured or refined.
Suitable natural oils and fats are: vegetable oils such as olive oil, safflower oil, soybean oil, groundnut oil, cotton oil, corn oil, rape oil, castor oil, sunflower oil, coffee oil, linseed oil, coconut fat and mixtures thereof, animal fats and oils such as fish oils, e.g. sardine oil, herring oil, salmon oil, shark-liver oil or whale oil, and further tallow oil, bone oil, woolfat fractions and bovine tallow.
The following vegetable oils are preferred: castor oil, soybean oil, rape oil and corn oil. Particularly preferred of these is castor oil.
Per mol of the triglyceride on which the oil is based, from 1 to 100, preferably from 10 to 35 and in particular from 15 to 30, mol of ethylene oxide and/or propylene oxide are employed.
Suitable bases are especially inorganic bases such as the alkali metal or alkaline earth metal hydroxides, e.g. sodium hydroxide, potassium hydroxide or calcium hydroxide. Instead of the direct use of hydroxides, it is possible to use carbonates or hydrotalcites, which, if appropriate, were hydrophobized with aliphatic or aromatic carboxylic acids, alcohols having 4 to 22 carbon atoms or the ethoxylates of alcohols of this type, or basic alkaline earth metal phosphates such as strontium phosphate, barium phosphate and calcium phosphate, each of which also form hydroxide ions in the presence of small amounts of water.
The base particularly used is potassium hydroxide.
Per mol of triglyceride, from 0.1 to 5, and in particular from 0.1 to 2, % by weight of base, based on the weight of the triglyceride, are generally added to the reaction mixture.
The reaction is generally carried out at elevated pressure, preferably at from 1 to 10 and in particular at from 1 to 5 bar and at from 80 to 230 and especially from 100 to 150xc2x0 C.
Working-up is in general carried out such that excess ethylene oxide or propylene oxide is removed under reduced pressure.
Otherwise, the carrying-out of such alkoxylation reactions and the isolation of the resulting reaction products is known to the person skilled in the art (cf. N. Schxc3x6nfeldt, Grenzflxc3xa4chenaktive Ethylenoxidaddukte [Surface-active ethylene oxide adducts], Wissenschaftliche Verlagsgesellschaft mbH, Stuttgart, 1984).
A particularly preferred product for component b1 is the product obtainable by the reaction of an oil/fat based on a triglyceride of carboxylic acids having 10 to 20 carbon atoms and 10 to 30 mol equivalents of ethylene oxide and/or propylene oxide in the presence of hydroxide ions.
Preferred as component b2 are the esters derived from C8-C28 fatty acids with C5- and/or C6 sugar alcohol polyethoxylates comprising preferably of from 10 to 100, particularly 20 to 50 ethoxylate units.
Preferred fatty acids are oleic acid, stearic acid, pelargonic acid and 2-Ethylhexanoic acid or mixtures thereof.
Component b can be solely constituted of component b1 or b2 or of mixtures of both species.
Component b constitutes up to 99.9, preferably 0.5 to 50, in particular 0.5 to 25% by weight of the formulations in accordance with the instant invention.
The formulations according to the invention can moreover additionally contain further customary additives such as surfactants, antifoams, cosolvents, etc.
Suitable surfactants are:
anionic surfactants, e.g. alkali metal, alkaline earth metal or ammonium salts of the fatty acids such as potassium stearate, alkylsulfates, alkyl ether sulfates, alkyl- or isoalkylsulfonates, alkylbenzenesulfonates such as Na dodecylbenzenesulfonates, alkylnaphthalenesulfonates, alkylmethyl ester sulfonates, acylglutamates, alkylsuccinic acid ester sulfonates, sarcosinates such as sodium lauroyl sarcosinate or taurates,
cationic surfactants, e.g. alkyltrimethylammonium halides or alkylsulfates, alkylpyridinium halides or dialkyldimethylammonium halides or alkylsulfates,
nonionic surfactants, e.g. alkoxylated animal or vegetable fats and oils such as corn oil ethoxylates, castor oil ethoxylates, tallow fat ethoxylates, glycerol esters such as glycerol monostearate, fatty alcohol alkoxylates and oxo-alcohol alkoxylates, fatty acid alkoxylates such as oleic acid ethoxylates, alkylphenyl alkoxylates such as isononylphenol ethoxylates, fatty amine alkoxylates, fatty acid amide alkoxylates, sugar surfactants such as sorbitan fatty acid esters (sorbitan monooleate, sorbitan tristearate), polyoxyethylenesorbitan fatty acid esters, alkyl polyglycosides, N-alkylgluconamides, alkylmethyl sulfoxides, alkyldimethylphosphine oxides such as tetradecyldimethylphosphine oxide,
zwitterionic surfactants, e.g. sulfobetaines, carboxybetaines, alkyldimethylamine oxides such as tetradecyldimethylamine oxide,
polymer surfactants, e.g. di-, tri- or multi-blockpolymers of the type (AB)x, ABA and BAB such as polyethylene oxide-block-polypropylene oxide, polystyrene-block-polyethylene oxide, AB comb polymers such as polymethacrylate or polyacrylate comb-polyethylene oxide,
perfluoro surfactants, silicone surfactants, phospholipids such as lecithin, amino acid surfactants such as N-lauroyl glutamate, surface-active homo- and copolymers such as polyvinylpyrrolidone, polyacrylic acid, polyvinyl alcohol, polyethylene oxide, maleic anhydride-isobutene copolymers, vinylpyrrolidone-vinyl acetate copolymers.
Preferably, the surfactant used is one or more homogeneous or mixed esters of phosphoric acid or diphosphoric acid with polyalkylene oxide ethers, the polyalkylene oxide ethers generally having only a single hydroxyl group (e.g. Klearfac(copyright), manufacturer: BASF Corp.).
Suitable polyalkylene oxide ethers are, for example, ethers of alkylphenols such as nonylphenol or of branched or unbranched aliphatic alcohols, for example having 6 to 30, preferably having 10 to 20, carbon atoms and in particular of fatty alcohols having 10 to 12 carbon atoms.
The monohydroxylated polyalkylene oxide ethers are generally known or accessible in a manner known per se, especially by alkoxylation of the corresponding alcohols. Preferred alkoxylating agents are ethylene oxide and propylene oxide, which can be reacted with a suitable phosphorus compound individually, in a mixture, in succession or alternately, by means of which alkoxylation products of differing composition, for example having block structures, can result.
The preparation of these phosphoric acid esters is generally known and is carried out, for example, by reaction of the corresponding monofunctional polyalkylene oxide ether with phosphoric acid, diphosphorus pentoxide, polyphosphoric acid or phosphorus oxytrichloride (cf. xe2x80x9cNonionic Surfactantsxe2x80x9d, Martin Schick (Ed.), Marcel Dekker, New York, 1964, Chapter 11, pages 372-394).
The proportion of the surfactants can be from 0 to 30, preferably from 2 to 15, % by weight.
Suitable antifoams are aliphatic or aromatic monoalcohols having 4 to 14, preferably 6 to 10, carbon atoms, such as n-octanol or n-decanol or silicone surfactants.
The proportion of the antifoams in the mixture is normally from 0.5 to 15 and especially from 3 to 8% by weight.
Suitable cosolvents are mineral oils, naturally occurring oils such as rape oil, soybean oil and the methyl esters of carboxylic acids on which these oils are based, such as methyl oleate and rape oil methyl ester, fatty acid esters, especially with C1-C4-alkanols and organic solvents such as benzenes or naphthalenes substituted by straight-chain or branched alkyl groups (Shellsol 150(copyright), Shellsol 200(copyright) and Solvesso(copyright) brands).
The proportion of the cosolvents in the mixture can be from 1 to 60 and especially from 5 to 30% by weight.
Furthermore, the mixture can contain from 0 to 15 and especially from 2 to 10% by weight of water.
Additionally, the mixture can contain one or more carboxylic acids having from 4 to 20, in particular from 6 to 18, carbon atoms such as oleic acid or 2-ethylhexanoic acid and/or one or more of the dicarboxylic acids on which the compounds I are based, e.g. adipic acid, sebacic acid or succinic acid.
The proportion of these (di)carboxylic acids in the mixture is from 0 to 30, preferably from 0 to 10, % by weight.
As component d) the plant growth regulating formulations in accordance with the instant invention can additionally contain further known plant growth regulating compounds.
The biological activity of 16,17-dihydro GAs can be improved in a synergistic manner (cf. S. R. Colby, Weeds 25: 20-22) by co-applying them with other plant growth regulators. This is particularly observed when using the preferred compounds VI or VII in formulations or spray solutions in combination with other growth retardants, i.e. compounds leading to a reduction of shoot length.
Plant growth retardants of practical relevance are, for instance,
ethephon (standard compound I), the quaternary ammonium compounds
chlormequat chloride (standard compound II)
mepiquat chloride (standard compound III),
compounds possessing a N-containing heterocycle
ancymidol
flurprimidol
paclobutrazol
uniconazole-P
inabenfide, the acylcyclohexanediones
prohexadione-Ca (standard compound IV)
trinexapac-ethyl (standard compound V)
16,17-dihydro GAs are also suitable to synergize the biological activity of exogenously applied gibberellins, such as gibberellic acid (GA3=compound VI) or other GAs with immediate biological activity (e.g. GA4, GA7). The commercially available GA3 and GA4+7 have found a large number of applications [for details see Thomson, W. H. (1995) Agricultural Chemicals, Book III, Thomson Publications, Fresno, USA, p. 29-35].
Particularly in graminaceous species, the preferred compounds VI and VII synergize the action of exogenously applied GAs and can, thus, be used to
increase the yield of malt and decrease the amount of time required for the malting process in the brewing industry
increase the yield of sugar cane
stimulate germination and seedling development in rice, wheat, barley, oats, rye, maize, sorghum, turf grasses and other plant species.
In addition to enhancing the biological performance of 16,17-dihydro-GAs by using suitable adjuvants for the preparation of formulations, additional optimisation can be achieved by adding further adjuvants to the spray solution (tank mixing). Particularly preferred adjuvants are ammonium sulphate or citric acid added at a concentration of from 0.01 to 0.5% by weight, preferably 0.05 to 0.2% by weight.